1. Field of the Invention
This invention relates to a closed system in which predetermined amounts of concentrate are mixed with the carrier liquid to produce a solution, and in one aspect, to a system for mixing predetermined amounts of toxic concentrates of chemicals with water to provide a solution meeting specifications for janitorial services.
2. Description of the Prior Art
Systems for delivering different additive fluids in controlled amounts to equipment utilizing those fluids, such as laundry or dishwashing equipment, are known. Such systems include the use of pumps and valves to automatically feed the additive fluid into the carrier liquid to provide a solution for performing the washing or rinsing function in the equipment. One such patent is U.S. Pat. No. 4,090,475, which discloses an apparatus to deliver a laundry system or dishwashing system different liquid detergents, soaps, water softeners, bleach, or other additive liquids or solutions and comprises a system wherein a pump is used for delivering a plurality of different additive fluids to the equipment, which valves are operated in a timed sequence during the operation of the pump to allow the additive fluid to enter the carrier fluid and then the pump operates to pump the flushing liquid through the chamber to flush the chamber and pump. The injection valves and flushing equipment are controlled by a number of different timers interconnected to operate the respective valves sequentially through predetermined intervals. Even positive displacement pumps operating with solenoid valves for predetermined intervals cannot give accurate measured amounts of the additive fluid or a measured amount of carrier liquid since changes in the line voltage of the power source to the solenoid valves and to the pump and changes in pressure in the line for the flushing water cause a variation in the timing cycle during operation of the system and in the composition of the solution supplied to the equipment. Other systems for supplying chemicals to laundry or dishwashing equipment, such as illustrated in U.S. Pat. No. 3,826,113, use a series of pumps, one connected to each fluid product, and an electrical timing network for the system which further compounds the chance for error.
It is therefore important to such systems that the pressure on the water supply and the amount of additive fluid be precise as possible to provide the proper amount of solution at the proper strength.
Accuracy as to the amount of additive fluid and the amount of carrier fluid is particularly important when the strength of the solution is important to obtain the result desired. Therefore, it is important that the system be free of any influence from environmental changes on what the resulting solution will be.